Being married to someone with dementia may sharply increase your own risk of developing the condition, a new study shows.
Utah researchers found that seniors had six times the risk of developing dementia if they lived with a spouse who had been diagnosed with the condition, according to the study, which was published in the Journal of the American Geriatrics Society. And the increased risk was substantially higher for husbands than for wives.
“The good news is that most of the spouses did not develop dementia,” said the study’s lead author, Maria Norton, an associate professor in the department of Family, Consumer and Human Development at Utah State University, in Logan. “But this does alert us to the increased risk for some of them. We need to be taking care of the caregiver and finding ways to maximize the positives of care giving.”
The study followed 1,221 couples for 12 years. All 2,442 study volunteers were at least 65 years old and free of dementia at the outset. By the end of the study, 255 of the seniors had developed dementias, two-thirds of which were Alzheimer’s disease.
Though the study did not explicitly ask whether spouses had taken on the role of caregiver, Norton says it’s safe to assume they did.
She and her colleagues were so surprised by their findings that they ran their numbers again, this time accounting for the spouses’ ages, genders and whether they had a form of the APOE gene that raises the risk for Alzheimer’s disease. In their new analysis, they also factored in socio-economic status, which can be a surrogate for shared environmental risk factors, such as access to medical care, diet and exercise.
The number barely budged: having a spouse with dementia still resulted in a six-fold increased risk of developing the condition. And the news was far worse for men: increase was almost 12-fold, as compared to a four-fold increase in women.
Norton and her colleagues don’t yet know what is at the root of the hike in risk. It’s entirely possible that there are environmental factors that we don’t yet know about, Norton said. “Controlling for economic status is not the same as controlling for the 5,000 things that people can share,” she said.
Finding the reason for the increased risk of dementia will be the focus for future research.
“We need more studies to determine how much of this association is due to caregiver stress and how much of it might be due to a shared environment,” she said. “It’s possible that we’ll find that there is something that the caregivers who developed dementia had in common, such as a particular personality trait or their coping styles. Or, maybe it isn’t as much about the caregiver so much as it is about the spouse who gets dementia first: how rapidly they decline, whether they have delusions. Not all dementias are the same. Some might be more stressful to the caregiver.”
An expert unaffiliated with the new study called the finding “compelling,” but not necessarily surprising.
“Caregiving is very stressful,” said Dr. Gary W. Small, director of the University of California-Los Angeles, Center on Aging and director of the Geriatric Psychiatry Division at the Semel Institute for Neuroscience and Human Behavior at the David Geffen School of Medicine at UCLA. “Studies have shown that caregivers for dementia patients have a high risk for major clinical depression. And there has been a study that showed that people who are prone to stress are at higher risk for Alzheimer’s.”
Other research has shown that stress can damage a part of the brain that is involved with memory. “Studies have shown that lab animals under stress have fewer cells in the hippocampus,” Small said. “And when human volunteers are injected with the stress hormone cortisol, they end up with a temporary impairment of memory.”
Small suspects that the husbands had a higher risk of dementia than the wives because men are not as used to taking on the role of caregiver as women in our society. “That finding is consistent with the sex specific roles that people still tend to take on in marriage,” he explained.
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